1. Field of the Invention
The present invention relates to a gear box, and more particularly to a gear box used for a motor reducer.
2. Description of the Related Art
In the conventional practice, small-sized direct-current (DC) motors are used in electrical equipment for use in vehicle and other various types of apparatuses and devices. Here, the electrical equipment for use in vehicle includes an opening-and-closing apparatus for a power window mechanism (power window switchgear), an automotive opening-and-closing apparatus for a door-locking mechanism (automotive door-locking switchgear), an electric mirror surface driving/retracting apparatus, and an air conditioner, for instance. A motor unit in which a reducer for regulating the torque and the rotational speed of a motor is formed integrally with the motor is used in such equipment.
For example, Japanese Patent No. 3568415 discloses a motor unit comprising a housing, which is integrally molded by a synthetic resin, a DC motor fixed to the housing, and a speed reduction mechanism held inside the housing. A plurality of electric terminals (hereinafter referred to as “terminals” also) with which the signal lines from an electronic control unit and the power wires from a battery power supply are connected to the DC motor or circuit board are insert-molded into a connector portion of this motor unit. Also, the connector portion thereof is integrally formed with the housing using the synthetic resin.
It is to be noted here that, in the above-described motor unit, the motor and the connector portion are provided opposite to each other with the housing for holding a worm wheel therein located between the motor and the connector portion. As a result, the total length of the motor unit gets longer.
Also, there are cases where a terminal functioning as a power feeding passage leading from the connector portion to the motor is provided within the housing. In such a case, conceivable is a method where the housing is manufactured before the terminal is placed at a predetermined position within the housing. However, it is not easy to accurately place and secure the terminal onto a positioning portion in the housing. Accordingly, there is room for improvement in the method of manufacturing the housing where the terminal is provided.